Multiple projectile sabot assembly for use in rifled barrel

ABSTRACT

1. In combination with a rifled gun barrel having lands and grooves in the bore, a sabot assembly comprising: A. A SABOT CONFIGURATION INCLUDING A SABOT WHOSE DIAMETER IS THE SAME AS THE DIAMETER OF SAID LANDS, A PLURALITY OF SUB-CALIBER PROJECTILES CONTAINED IN SAID SABOT, AND A PUSHER DISC WHOSE DIAMETER IS THE SAME AS THE DIAMETER OF SAID LANDS; B. SAID SABOT AND PUSHER DISC BEING SLIDEABLY ENGAGED WITH SAID LANDS AND SAID PUSHER DISC BEING ENGAGED WITH SAID SABOT FOR PUSHING THE SAME THROUGH SAID BORE UNDER THE INFLUENCE OF PROPELLENT GASES THEREIN; C. A DEFORMABLE OBTURATOR DISC MEANS HAVING AN ANTI-FRICTION SURFACE CONNECTION WITH SAID SABOT PUSHER DISC AND BEING INTERPOSED BETWEEN THE PROPELLANT GASES AND SAID PUSHER DISC; D. SAID OBTURATOR DISC HAVING A NOMINAL DIAMETER THAT IS THE SAME AS THE DIAMETER OF SAID GROOVES AND BEING DEFORMED BY ENGAGEMENT WITH THE LANDS AND GROOVES OF SAID BORE; AND E. SAID OBTURATOR DISC SERVING TO PUSH THE CONFIGURATION THROUGH THE BORE AND PREVENT PROPELLENT GASES FROM BLOWING PAST THE CONFIGURATION.

United States Patent La Costa Apr. 9, 1974 1 1 MULTIPLE PROJECTILE SABOT ASSEMBLY FOR USE IN RIFLED BARREL EXEMPLARY CLAIM FOREIGN PATENTS OR APPLICATIONS Nicholas Joseph La Costa, Phoenix, Md.

AAI Corporation, Cockeysville, Md.

May 2, 1962 Inventor:

Assignee:

Filed:

Appl. No.:

us. (:1 102/93, 102/38, 102/42 c,

102/63, 102/91,10g/22A.g 110. C1. F42b 13/16 Field of Search 102/93,94,95, 38,91,

References Cited UNITED STATES PATENTS H1894 Germany 102/91 Primary ExaminerRobert F. Stahl Attorney, Agent, or FirmReginald F. Pippin, Jr.

1. In combination with a rifled gun barrel having lands and grooves in the bore, a sabot assembly comprising:

a. a sabot configuration including a sabot whose diameter is the same as the diameter of said lands, a plurality of sub-caliber projectiles contained in said sabot, and a pusher disc whose diameter is the same as the diameter of said lands;

b. said sabot and pusher disc being slideably engaged with said lands and said pusher disc being engaged with said sabot for pushing the same through said bore under the influence of propellent gases therein;

c. a deformable obturator disc means having an anti-friction surface connection with said sabot pusher disc and being interposed between the propellant gases and said pusher disc;

d. said obturator disc having a nominal diameter that is the same as the diameter of said grooves and being deformed by engagement with the lands and grooves of said bore; and

e. said obturator disc serving to push -the configuration through the bore and prevent propellent gases from blowing past the configuration.

7 Claims, 5 Drawing Figures NENTEBMR 9 I974 NICHOLAS J. La COSTA INVENTOR.

MULTIPLE PROJECTILE SABOT ASSEMBLY FOR USE IN RIFLED BARREL This invention relates to pusher-type sabots, and more particularly to a pusher-type sabot configuration containing a cluster of elongated subcaliber spinstabilized projectiles.

A pusher-type sabot is one which has a portion interposed between the propellent gases in a gun bore, and the sub-caliber projectile means carried by the sabot. Such portions seals the propellent gases in the bore and serves to push the projectile means therethrough.

Under certain conditions, ammunition incorporating a sabot configuration of the class described is more advantageous than conventional ammunition. Optimum results would be achieved if it were possible to easily switch a weapon from one type of ammunition to the other to meet the exigency of a particular situation. However, the weapon requirements for the two ammunitions are in conflict because conventional ammunition requires a rifled barrel, and previous to this invention, sabot ammunition incorporating a cluster of subcaliber projectiles required a smooth bore weapon. Where a sabot includes an obturator portion to seal the propellent gases and prevent them from blowing past the sabot, such portion would be engageable with the grooves and lands of the rifling, thereby causing the sabot to spin rapidly. A cluster of projectiles contained in a spinning sabot would produce a dispersion pattern so wide that ammunition of this type becomes ineffective. For this reason, it is conventional to utilize a smooth bore weapon if the dispersion pattern is to be as small as possible.

It is therefore an object of this invention to provide a sabot assembly which can be used in a rifled barrel interchangeably with conventional ammunition and which will produce a dispersion pattern of the same order of magnitude as a sabot configuration launched from a smooth bore weapon. As a feature of this invention whereby the object thereof is achieved, the portion of the sabot assembly housing the projectiles is made separate from the portion forming the obturator seal so that the seal transmits thrust to the sabot assembly but not spin.

Briefly, the invention includes a sabot configuration containing the elongated sub-caliber projectiles which is the same diameter as the lands of the rifling, and a deformable obturator disc of the same diameter as the grooves. The coefficient of friction between the obturator disc and the sabot configuration is made as low as possible so that the disc transmits thrust to the sabot configuration but not the spin imparted to the disc by the rifling.

The more important features of this invention have thus been outlined rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will also form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for designing other structures for carrying out the several purposes of this invention. It is important, therefore, that the claims to be granted herein shall be of sufficient breadth to prevent the appropriation of this invention by those skilled in the art.

In the drawing:

FIG. 1 is a side view of a round of ammunition incorporating a multiple projectile sabot assembly with parts broken away to better illustrate the construction of the assembly.

FIG. 2 is a side section view of a multiple projectile sabot assembly after the round is fired.

FIGS. 3 and 4 are sectional views taken along the lines 3-3 and 4-4, respectively, of FIG. 2.

FIG. 5 is a modification of the assembly shown in FIGS. 1 and 2.

Ammunition into which the present invention is incorporated is shown generally at in FIG. I. Ammunition 10 includes casing 1], powder charge 12 and sabot assembly 13. In outward appearance, round 10 is the same as a conventional round.

Casing 11 includes base 14 and cylindrical side walls 15. Centrally located in base 14 is primer 16 connected by port 17 to the interior of the casing. Base 14 has extractor groove 18 therein.

Powder charge 12 is contained within the walls between base 14 and assembly 13 which is inserted in the open end of the casing and crimped thereto as at 19. Assembly 13 includes sabot configuration 20, and obturator disc 21. Configuration 20 includes segmented sabot 22, pusher disc 23, and a plurality of elongated sub-caliber spin-stabilized projectiles 24.

Sabot 22 is preferably made in quarters and when assembled is the same diameter as the lands 25 in bore 26 v of rifled barrel 27. Sabot 22 has coaxial hole 28 at the rear thereof that is somewhat larger in diameter than the main coaxial hole 29 in the mid-portion of the sabot so that fins 29 of projectiles 24 make a snug fit when packed therein. Coaxial port 32 at the front of the sabot connects separation bore 31 at the nose of the sabot to bore 29.

Pusher disc 23 of assembly 13 is preferably made from steel to absorb projectile set back when the round is fired. Obturator disc 21 is preferably made from Teflon or the like so that there is a low coefficient of friction between 21 and disc 23 of configuration 20. Furthermore, disc 21 is of the same diameter as the grooves of the rifling of barrel 27, and has a tapered obturating flange 33 that extends circumferentially on the rear exposed face of the disc. Disc 21 is deformable by lands 25 of the rifling when moved axially in the bore so that the disc fills the bore completely and prevents propellent gases from blowing past the configuration. The deformation of flange 32 by the rifling serves to impart a spin to disc 21 when the gases thrust it through the bore.

In operation, round 10 would be loaded into a weapon and fired in a conventional manner by causing a firing pin(not shown) to strike primer 16 causing ignition of charge 12. The resultant gases react against disc 21 causing assembly 13 to be thrust into the rifling of the barrel of the weapon. Disc 23 absorbs the projectile set back. Configuration 20, being of the same diameter as lands 25, merely slideably engages the latter and is not spun by the rifling (see FIG. 3). Disc 21, on the other hand, being of the same diameter as grooves 30, is deformed by the rifling and caused to spin (see FIG. 4). The propellent gases react against flange 32, pressing the latter into tight engagement with the bore of the barrel and effectively sealing the gases against blowing past the assembly. Because of the low coefficient of friction between the disc 21 and disc 23, spin imparted to disc 21 by the rifling is not imparted to configuration 20. Thus, disc 21 is effective to impart a thrust to the donfiguration without imparting any spin.

Upon muzzle exit, air enters orifice 31 and the pressure strips the sabot from the cluster 24 of projectiles 24. Such cluster, because it has not been spun up by the rifling, has substantially the same dispersion characteristics as a cluster launched from a smooth-bore weapon.

While FIGS. 1 and 2 illustrate a Teflon-metal combination for discs 21 and 23, other combinations have proven to be successful. For example, a lubricant, such as molybdenum disulfide can be used to advantage between 21 metal-to-metal combination; or, small ball bearings or Teflon discs could be inserted between the discs whereby they act as a miniature thrust bearing. Whether the combination is Teflon-metal, or metal-tometal with a lubricant or ball bearings therebetween, the obturator disc may properly be described as being provided with means for reducing the coefficient of friction between the obturator disc and the sabot configuration.

In order to prevent the pusher disc from impacting lands 25, the modification of FIG. 5 can be used. Here, configuration includes segmented sabot 22 containing a cluster of sub-caliber projectiles and pusher disc 23'. Centered in the rear surface of disc 23' is circular recess 40 into which boss 41, centrally located on the front of obturator disc 21', rotatably fits. The engagement of boss 41 in recess 40 prevents radial shifting or balloting of disc 23', and so prevents the edges of the disc from impacting lands 25. The remaining operation is the same as previously described.

What is claimed is:

I. In combination with a rifled gun barrel having lands and grooves in the bore, a sabot assembly comprising:

a. a sabot configuration including a sabot whose diameter is the same as the diameter of said lands, a plurality of sub-caliber projectiles contained in said sabot, and a pusher disc whose diameter is the same as the diameter of said lands;

b. said sabot and pusher disc being slideably engaged with said lands and said pusher disc being engaged with said sabot for pushing the same through said bore under the influence of propellent gases therein;

c. deformable obturator disc means having an antifriction surface connection with said sabot pusher disc and being interposed between the propellent gases and said pusher disc;

d. said obturator disc having a nominal diameter that is the same as the diameter of said grooves and being deformed by engagement with the lands and grooves of said bore; and

e. said obturator disc serving to push the configuration through the bore and prevent propellent gases from blowing past the configuration.

2. The device of claim 1 wherein said pusher disc is metallic, and including a polyfluorethylene surface connection at said interface of said pusher disc and obturator disc whereby there is a low coefficient of fricton between the two discs and spin imparted to the obturator disc by said lands and grooves as it pushes said configuration through said bore is not significantly transferred to said configuration.

3. For use in a rifled gun barrel having lands and grooves in the bore, a sabot assembly comprising:

a. a sabot configuration including a sabot whose diameter is the same as the diameter of said lands, a plurality of sub-caliber projectiles contained in said sabot, and a pusher disc whose diameter is the same as the diameter of said lands;

b. said sabot and pusher disc being slideably engaged with said lands and said pusher disc being engaged with said sabot for pushing the same through said bore under the influence of propellent gases therein;

c. a deformable obturator disc interposed between the propellent gases and said pusher disc;

d. said obturator disc having a nominal diameter that is the same as the diameter of said grooves and being deformed by engagement with the lands and grooves of said bore;

e. said obturator disc serving to push the configuration through the bore and prevent propellent gases from blowing past the configuration;

f. the engagement of said obturator disc with said lands and grooves imparting a spin to said obturator disc; and

g. said obturator disc being provided with means to reduce the coefficient of friction between the obturator disc and the pusher disc for minimizing the amount of spin imparted to said sabot configuration when the latter is pushed through the bore by said obturator disc.

4. The device of claim 3 wherein said obturator disc is rotatably mounted on said pusher disc.

5. The device of claim 3 wherein said means to reduce the coefficient of fricton is the dissimilarity in materials between the obturator disc and the pusher disc.

6. In combination with a rifled gun barrel having lands and grooves in the bore, a sabot assembly comprising:

a. a sabot configuration including a sabot whose diameter is the same as the diameter of said lands, and a plurality of sub-caliber projectiles contained in said sabot;

b. said sabot being slideably engaged with said lands;

c. obturator means engaged with said lands and grooves and adapted to be thrust and spun through the bore is response to propellent gases therein; and

d. said obturator means being engaged with said sabot configuration for transmitting thrust thereto without transmitting spin.

7. The device of claim 6 wherein said sabot configuration includes a metallic pusher disc engaged with said obturator means, and the material of said obturator means is Teflon. 

1. In combination with a rifled gun barrel having lands and grooves in the bore, a sabot assembly comprising: a. a sabot configuration including a sabot whose diameter is the same as the diameter of said lands, a plurality of sub-caliber projectiles contained in said sabot, and a pusher disc whose diameter is the same as the diameter of said lands; b. said sabot and pusher disc being slideably engaged with said lands and said pusher disc being engaged with said sabot for pushing the same through said bore under the influence of propellent gases therein; c. deformable obturator disc means having an anti-friction surface connection with said sabot pusher disc and being interposed between the propellent gases and said pusher disc; d. said obturator disc having a nominal diameter that is the same as the diameter of said grooves and being deformed by engagement with the lands and grooves of said bore; and e. said obturator disc serving to push the configuration through the bore and prevent propellent gases from blowing past the configuration.
 2. The device of claim 1 wherein said pusher disc is metallic, and including a polyfluorethylene surface connection at said interface of said pusher disc and obturator disc whereby there is a low coefficient of fricton between the two discs and spin imparted to the obturator disc by said lands and grooves as it pushes said configuration through said bore is not significantly transferred to said configuration.
 3. For use in a rifled gun barrel having lands and grooves in the bore, a sabot assembly comprising: a. a sabot configuration including a sabot whose diameter is the same as the diameter of said lands, a plurality of sub-caliber projectiles contAined in said sabot, and a pusher disc whose diameter is the same as the diameter of said lands; b. said sabot and pusher disc being slideably engaged with said lands and said pusher disc being engaged with said sabot for pushing the same through said bore under the influence of propellent gases therein; c. a deformable obturator disc interposed between the propellent gases and said pusher disc; d. said obturator disc having a nominal diameter that is the same as the diameter of said grooves and being deformed by engagement with the lands and grooves of said bore; e. said obturator disc serving to push the configuration through the bore and prevent propellent gases from blowing past the configuration; f. the engagement of said obturator disc with said lands and grooves imparting a spin to said obturator disc; and g. said obturator disc being provided with means to reduce the coefficient of friction between the obturator disc and the pusher disc for minimizing the amount of spin imparted to said sabot configuration when the latter is pushed through the bore by said obturator disc.
 4. The device of claim 3 wherein said obturator disc is rotatably mounted on said pusher disc.
 5. The device of claim 3 wherein said means to reduce the coefficient of friction is the dissimilarity in materials between the obturator disc and the pusher disc.
 6. In combination with a rifled gun barrel having lands and grooves in the bore, a sabot assembly comprising: a. a sabot configuration including a sabot whose diameter is the same as the diameter of said lands, and a plurality of sub-caliber projectiles contained in said sabot; b. said sabot being slideably engaged with said lands; c. obturator means engaged with said lands and grooves and adapted to be thrust and spun through the bore is response to propellent gases therein; and d. said obturator means being engaged with said sabot configuration for transmitting thrust thereto without transmitting spin.
 7. The device of claim 6 wherein said sabot configuration includes a metallic pusher disc engaged with said obturator means, and the material of said obturator means is Teflon. 